Heater block



FIG. 1 is a top view of a first embodiment of a heater block in accordance with our design;

FIG. 2 is a front view thereof;

FIG. 3 is a bottom view thereof;

FIG. 4 is a cross-section thereof taken along line 4-4 of FIG. 1;

FIG. 5 is a top view of a second embodiment of a heater block in accordance with our design;

FIG. 6 is a front view thereof;

FIG. 7 is a right side view thereof;

FIG. 8 is a left side view thereof;

FIG. 9 is a back view thereof;

FIG. 10 is a bottom view thereof; and,

FIG. 11 is cross-section thereof taken along line 11-11 of FIG. 5.

The broken lines illustrate portions of the heater block which form no part of the claimed design. 

CLAIM The ornamental design for a heater block, as shown and described. 